High solids edge coatings for building panels

ABSTRACT

Described herein is a coating composition suitable for application to a building panel. The coating composition comprises inorganic pigment, liquid carrier, and a humectant comprising a first ester-containing compound. The liquid carrier may be present in an amount ranging from about 10 wt. % to about 30 wt. % based on the total weight of the coating composition. Described herein are also building panels coated with the coating composition and methods of their production.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/551,514, filed on Aug. 29, 2017. The disclosure of the aboveapplication is incorporated herein by reference.

BACKGROUND

Ceiling systems are installed into room environments to help controlnoise as well as enhance the aesthetic appeal of those roomenvironments. These ceiling systems may comprise one or more buildingpanels having specific aesthetic properties that help contribute to theappeal of the room environment. Previous attempts at improving theaesthetic properties of these building panels included applyingdecorative coatings to the surface of the building panel. However, suchdecorative coatings tend to have associated difficulties inunpredictability in pot-life and manufacturing time required for properapplication and drying of the decorative coatings. Thus, a need existsfor building panels comprising a decorative coating applied thereto thatdoes not create the same difficulties with respect to manufacturing andwhile also not sacrificing the required aesthetic properties provided bythe decorative coating.

BRIEF SUMMARY

According to some embodiments, the present invention is directed to acoated building panel comprising a body comprising a first major surfaceand a side surface that intersects the first major surface; a coatingapplied to at least one of the first major surface or the side surface,the coating comprising inorganic pigment, and a humectant comprising afirst ester-containing compound; wherein the surface coating comprises aliquid carrier in an amount less than about 1 wt. % based on the totalweight of the coating.

In other embodiments, the present invention includes a coatingcomposition comprising inorganic pigment; liquid carrier; and ahumectant comprising a first ester-containing compound; and wherein theliquid carrier is present in an amount ranging from about 10 wt. % toabout 30 wt. % based on the total weight of the coating composition.

Other embodiments of the present invention include a method of forming abuilding panel having a face coating, the method comprising: a) applyinga coating composition to a surface of a body, the coating compositioncomprising an inorganic pigment and a humectant comprising a firstester-containing compound; and b) drying the coating composition to formthe face coating on the body; wherein the coating composition has asolid's content ranging from about 10 wt. % to about 30 wt. % based onthe total weight of the coating composition.

Other embodiments of the present invention include a building materialcomprising inorganic fiber; inorganic pigment; polymeric binder; and ahumectant comprising a first ester-containing compound.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is top perspective view of a coated building panel according tothe present invention;

FIG. 2 is a cross-sectional view of the coated building panel accordingto the present invention, the cross-sectional view being along the IIline set forth in FIG. 1;

FIG. 3 is a ceiling system comprising the coated building panel of thepresent invention.

FIG. 4 is a cross-sectional close-up view of the edges of the buildingpanels according to the present invention;

FIG. 5 is a close-up view of a ceiling system comprising the coatedbuilding panel according to an alternative embodiment of the presentinvention, the close-up view being the portion identified by oval V inFIG. 3;

FIG. 6 is a graphical representation of viscosity increase of acomparative coating composition;

FIG. 7 is a graphical representation of viscosity increase of acomparative coating composition; and

FIG. 8 is a graphical representation of viscosity increase of thecoating composition according to the present invention.

DETAILED DESCRIPTION

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

As used throughout, ranges are used as shorthand for describing each andevery value that is within the range. Any value within the range can beselected as the terminus of the range. In addition, all references citedherein are hereby incorporated by referenced in their entireties. In theevent of a conflict in a definition in the present disclosure and thatof a cited reference, the present disclosure controls.

Unless otherwise specified, all percentages and amounts expressed hereinand elsewhere in the specification should be understood to refer topercentages by weight. The amounts given are based on the active weightof the material.

The description of illustrative embodiments according to principles ofthe present invention is intended to be read in connection with theaccompanying drawings, which are to be considered part of the entirewritten description. In the description of embodiments of the inventiondisclosed herein, any reference to direction or orientation is merelyintended for convenience of description and is not intended in any wayto limit the scope of the present invention. Relative terms such as“lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,”“down,” “top,” and “bottom” as well as derivatives thereof (e.g.,“horizontally,” “downwardly,” “upwardly,” etc.) should be construed torefer to the orientation as then described or as shown in the drawingunder discussion. These relative terms are for convenience ofdescription only and do not require that the apparatus be constructed oroperated in a particular orientation unless explicitly indicated assuch.

Terms such as “attached,” “affixed,” “connected,” “coupled,”“interconnected,” and similar refer to a relationship wherein structuresare secured or attached to one another either directly or indirectlythrough intervening structures, as well as both movable or rigidattachments or relationships, unless expressly described otherwise.Moreover, the features and benefits of the invention are illustrated byreference to the exemplified embodiments. Accordingly, the inventionexpressly should not be limited to such exemplary embodimentsillustrating some possible non-limiting combination of features that mayexist alone or in other combinations of features; the scope of theinvention being defined by the claims appended hereto.

Unless otherwise specified, all percentages and amounts expressed hereinand elsewhere in the specification should be understood to refer topercentages by weight. The amounts given are based on the active weightof the material. According to the present application, the term “about”means +/−5% of the reference value. According to the presentapplication, the term “substantially free” less than about 0.1 wt. %based on the total of the referenced value.

Referring to FIGS. 1 and 4, the present invention includes a coatedbuilding panel 100 (referred to herein as “building panel”) comprising afirst major surface 111 opposite a second major surface 112 and a sidesurface 113 that extends between the first major surface 111 and thesecond major surface 112, thereby defining a perimeter of the ceilingpanel 100. The side surface 113 may comprise an upper portion 113 a anda lower portion 113 b, wherein the upper portion 113 a is adjacent tothe first major surface 111 and the lower portion 113 b is adjacent tothe second major surface 112.

Referring to FIG. 3, the present invention may further include a ceilingsystem 1 comprising one or more of the building panels 100 installed inan interior space, whereby the interior space comprises a plenum space 3and an active room environment 2. The plenum space 3 provides space formechanical lines within a building (e.g., HVAC, plumbing, etc.). Theactive space 2 provides room for the building occupants during normalintended use of the building (e.g., in an office building, the activespace would be occupied by offices containing computers, lamps, etc.).

In the installed state, the building panels 100 may be supported in theinterior space by one or more parallel support struts 5. Each of thesupport struts 5 may comprise an inverted T-bar having a horizontalflange 31 and a vertical web 32. The ceiling system 1 may furthercomprise a plurality of first struts that are substantially parallel toeach other and a plurality of second struts that are substantiallyperpendicular to the first struts (not pictured). In some embodiments,the plurality of second struts intersects the plurality of first strutsto create an intersecting ceiling support grid 6. The plenum space 3exists above the ceiling support grid 6 and the active room environment2 exists below the ceiling support grid 6.

In the installed state, the first major surface 111 of the buildingpanel 100 may face the active room environment 2 and the second majorsurface 112 of the building panel 100 may face the plenum space 3. Thebuilding panel 100 may be installed according to at least twovariations. In a first variation, the building panel 100 is positionedentirely above the horizontal flange 31 of the support struts 5. In thefirst variation, at least a portion of the first major surface may beconcealed from the active room environment 2 by the horizontal flange 31because the horizontal flange 31 contacts the first major surface 111,thereby supporting it in the ceiling system 1. In the first variation,the entire side surface 113—including the upper portion 113 a and thelower portion 113 b—may be concealed from the active room environment 2by the horizontal flange 311. The second variation will be describedfurther herein.

Referring now to FIGS. 1 and 2, the building panel 100 of the presentinvention may have a panel thickness t₀ as measured from the first majorsurface 111 to the second major surface 112. The panel thickness t₀ mayrange from about 12 mm to about 40 mm—including all values andsub-ranges there-between. The building panel 100 may have a length L_(P)ranging from about 30 cm to about 310 cm—including all values andsub-ranges there-between. The building panel 100 may have a width W_(P)ranging from about 10 cm to about 125 cm—including all values andsub-ranges there-between.

The building panel 100 may comprise a body 120 and a surface coating 200applied thereto—as discussed further herein. The body 120 comprises anupper surface 121 opposite a lower surface 122 and a body side surface123 that extends between the upper surface 121 and the lower surface122, thereby defining a perimeter of the body 120. The body 120 may havea body thickness t₁ that extends from the upper surface 121 to the lowersurface 122. The body thickness t₁ may range from about 12 mm to about40 mm—including all values and sub-ranges there-between.

The body 120 may be porous, thereby allowing airflow through the body120 between the upper surface 121 and the lower surface 122—as discussedfurther herein. The body 120 may be comprised of a binder and fibers. Insome embodiments, the body 120 may further comprise a filler and/oradditive.

Non-limiting examples of binder may include a starch-based polymer,polyvinyl alcohol (PVOH), a latex, polysaccharide polymers, cellulosicpolymers, protein solution polymers, an acrylic polymer, polymaleicanhydride, epoxy resins, or a combination of two or more thereof.Non-limiting examples of filler may include powders of calciumcarbonate, limestone, titanium dioxide, sand, barium sulfate, clay,mica, dolomite, silica, talc, perlite, polymers, gypsum, wollastonite,expanded-perlite, calcite, aluminum trihydrate, pigments, zinc oxide, orzinc sulfate.

The fibers may be organic fibers, inorganic fibers, or a blend thereof.Non-limiting examples of inorganic fibers mineral wool (also referred toas slag wool), rock wool, stone wool, and glass fibers. Non-limitingexamples of organic fiber include fiberglass, cellulosic fibers (e.g.paper fiber—such as newspaper, hemp fiber, jute fiber, flax fiber, woodfiber, or other natural fibers), polymer fibers (including polyester,polyethylene, aramid—i.e., aromatic polyamide, and/or polypropylene),protein fibers (e.g., sheep wool), and combinations thereof.

Referring now to FIG. 2, the building panel 100 may further comprise thesurface coating 200 applied to at least one of the first major surface121 and/or the side surface 123 of the body 120. The surface coating 200may comprise a pigment that imparts a desired aesthetic appearance, suchas color. According to the present invention the term “color coating”and “surface coating” may be used interchangeably. The term “colorcoating” 200 refers to a surface coating 200 comprising a color pigmentand the resulting surface coating 200 exhibits a color on the visiblecolor spectrum—i.e., violet, blue, green, yellow, orange, or red. Thecolor coating 200 may also have a color of white, black, or grey. Thecolor coating 200 may further comprise combinations of two or morecolors—such a primary color (i.e., red, yellow, blue) as well as anachromatic color (i.e., white, grey).

A non-limiting example of a color coating 200 may be pink and producedfrom a combination of red and white pigments. Another non-limitingexample of a color coating 200 may be green and produced from acombination of blue and yellow pigments. Another non-limiting example ofa color coating 200 may be brown and produced from a combination of red,yellow, and black pigments.

In some embodiments, the surface coating 200 may include a face coating210 that is applied to the first major surface 121 of the body 120. Inother embodiments, the surface coating 200 may include an edge coating230 that is applied to the side surface 123 of the body 120. In otherembodiments, the building panel 100 may comprise both the face coating210 applied to the first major surface 121 of the body 120 as well asthe edge coating 230 applied to the side surface 123 of the body 120.

Referring now to FIG. 2, the edge coating 230 may comprise an outersurface 231 opposite an inner surface 232. The edge coating 230 has anedge coating thickness t₃ was measured from the outer surface 231 to theinner surface 232 of the edge coating 210. The edge coating thickness t₃may range from about 100 μm to about 600 μm—including all thicknessesand sub-ranges there-between. In a preferred embodiment, the edgecoating thickness t₃ may range from about 200 μm to about 500 μmincluding all thicknesses and sub-ranges there-between. The edge coating230 (i.e., in the dry-state) may be present in an amount ranging fromabout 7.5 g/m² to about 150 g/m²—including all amounts and sub-rangesthere-between.

According to the present invention, the phrase “dry-state” indicates acomposition that is substantially free of a liquid carrier (e.g., liquidwater). Thus, the edge coating 230 in the dry-state may comprise thepigment, the humectant, and the binder, and have less than about 0.1 wt.% of liquid carrier based on the total weight of the edge coating 230.In a preferred embodiment, the edge coating 230 in the dry-state has asolid's content of about 100 wt. % based on the total weight of the edgecoating 230. Conversely, a composition that is in a “wet-state,” whichrefers to a composition containing various amounts of liquid carrier—asdiscussed further herein.

The edge coating 230 may comprise a pigment and a humectant. The edgecoating 230 may further comprise a binder. In some embodiments, the edgecoating 230 may further comprise a dispersant and/or a wetting agent.

The edge coating 230 may be formed by applying an edge coatingcomposition in the wet-state having a solids content ranging from about70 wt. % to about 90 wt. %—including all amounts and sub-rangesthere-between. The edge coating composition in the wet-state maycomprise the pigment, the humectant, and the binder, as well as a liquidcarrier. he liquid carrier may be selected from water, VOC solvent—suchas acetone, toluene, methyl acetate—or combinations thereof. In apreferred embodiment, the liquid carrier is water and comprises lessthan 1 wt. % of VOC solvent based on the total weight of the liquidcarrier. The edge coating composition in the wet-state may furthercomprise the dispersant and/or wetting agent.

The solid's content is calculated as the fraction of materials presentin the edge coating composition (or face coating composition, asdiscussed herein) that is not the liquid carrier. Specifically, thesolid's content of the edge coating composition may be calculated as theamount of humectant, pigment, and binder in the edge coating compositionand dividing it by the total weight of the edge coating composition(including liquid carrier).

Therefore, the amount of each component in the edge coating compositionmay be calculated by multiplying the desired amount of each of thehumectant, pigment, and binder (as well as other additives, such asdispersant and/or wetting agent) present in the edge coating 230 in thedry-state by the total solids content of the edge coating composition.For example, for an edge coating 230 in the dry-state comprising about60 wt. % of pigment, whereby that edge coating 230 is formed from anedge coating composition having a solids content of 70 wt. %—the amountof the pigment in the edge coating composition would be 42 wt. % basedon the total weight of the edge coating composition in thewet-state—i.e., 60 wt. %×0.7=42 wt. % of pigment in the edge coatingcomposition.

The edge coating composition in the wet-state has a high-solid'scontent. According to the present invention, the term “high solidscontent” refers to a solids content of at least about 70 wt. % based onthe total weight of the edge coating composition. Stated otherwise, theliquid carrier is present in a maximum amount of about 30 wt. % based onthe total weight of the edge coating composition

Previously, using such pigments to create edge coatings (and other facecoatings) required that the wet-state coating composition comprise arelatively large amount of carrier—thereby resulting in low solidscontents for these coating compositions. Requiring a large amount ofcarrier stems from previous coating compositions having poor carrierretention characteristics. Such poor carrier retention creates asubstantial risk of the carrier being prematurely driven off the coatingcomposition during processing—for example, the carrier being evaporatedoff before the coating composition can be properly applied to one ormore surfaces 121, 123 of the body. Being at risk of premature carrierloss not only creates the risk of unwanted increases in viscosity of thecoating composition over time, but it also makes these increases inviscosity unpredictable as a single coating composition may be subjectedto various processing conditions depending on the type of coatingapplication desired, whereby each processing condition may have a uniqueimpact on the amount of carrier that is retained. Therefore, poorcarrier retention makes it harder and/or impossible to properly apply asingle coating composition to the body because that coating compositionmay be unworkable and/or have such a short pot-life that there wasinsufficient time to apply the coating composition in a large-scaleproduction of building panels.

The previous solution to such carrier retention issues was to overloadthe wet-state coating composition with liquid carrier. Excessive amountsof liquid carrier were added the coating composition to accommodate forthe amount of carrier that would be prematurely lost during processing.As a result, when carrier is prematurely lost and the viscosity of thecoating composition increases, the overall coating composition may stillremain under a viscosity threshold that is sufficiently low to allow forprocessing. However, adding such excessive amounts of carrier fails toaddress all issues associated with poor carrier retention because thesecoating compositions still prematurely lose carrier over time resultingin unpredictable viscosity changes as the coating composition isprocessed. Simply keeping the overall viscosity below a certainthreshold does not eliminate the unpredictable fluctuations in viscositythat are detrimental to processing and application of the coatingcomposition. Therefore, a need exists for a coating composition that canexhibit a stabilized viscosity overtime.

Additionally, coating compositions having such unpredictable carrierretention characteristics also create a chance that the coatingcomposition may not prematurely lose carrier during processing—ascarrier lose is entirely unpredictable. Therefore, when addressing theviscosity increase by overloading the coating compositions with carrier,other setbacks are created as the coating compositions may still retainlarge amounts of carrier at the time of application to the one or moresurfaces 121, 123 of the body. Having such large relative amounts ofcarrier—thereby resulting in low solids contents—at the time ofapplication is undesirable because it may result in poor aestheticappearance in the resulting edge coating and/or excessively long and/orresource intensive (e.g., heating temperature) drying periods that arerequired to properly drive off the excessive amounts of carrier from thecoating composition to form the dry-state surface coating 200. Thus,there exists a need to stabilize and reduce the evaporation of thecoating compositions while still having these coating compositions be ata relatively high solids content.

With this understanding, it has been surprisingly discovered that addinga humectant to the coating composition of the present invention providesthe needed viscosity stabilization by helping increase carrier retentionwhile not interfering with the other coating composition characteristicsneeded to properly apply the composition as a face coating in theproduction of the building panel. Humectants were previously known asbeing suitable in improving the freeze-thaw characteristics ofwater-based compositions—i.e., preventing unwanted freezing of suchcompositions at low temperatures. However, it has now been surprisinglydiscovered that the addition of humectants to water-based coatingcompositions allows for viscosity stabilization and increased carrierretention—even when the wet-state coating composition is being held at ahigh solids content. The unexpected benefit is that the coatingcompositions of the present invention may be applied under a variety ofapplication conditions without the risk of short pot-life or long curingtimes. Another unexpected advantage is that the addition of thehumectant reduces and/or eliminates building up of the coatingcomposition on the face of the coating applicator. Furthermore, whileother additives, such as dispersants and wetting agents, may be added tothe coating composition of the present invention, the addition of thehumectant allow for the elimination of VOC solvents such that thecarrier may be entirely water-based.

The humectant may be present in the edge coating 230 in an amountranging from about 0.4 wt. % to about 3.0 wt. %—including all amountsand sub-ranges there-between—based on the total dry weight of the edgecoating 230. The humectant may be present in the edge coatingcomposition in the wet-state in an amount ranging from about 0.25 wt. %to about 2.5 wt. %—including all amounts and sub-rangesthere-between—based on the total wet-weight of the edge coatingcomposition. The humectant may be non-ionic. The humectant may behydrophobic, as discussed in greater detail herein.

The humectant of the present invention may be an ester-containingcompound. The term “ester-containing compound” refers to a compoundhaving at least one ester bond, as shown herein:

Whereby R may include C1-C24 straight or branched aliphatic chain, oneor more additional ester groups, one or more ketone groups, orcombinations thereof. Group R′ may include a C1-C24 straight or branchedaliphatic chain, a compound derived from a carbohydrate, and acombination thereof. The carbohydrate may be a monosaccharide or adisaccharide. Non-limiting examples of monosaccharide include glucose,fructose, and galactose. Non-limiting examples of disaccharide includesucrose, lactulose, maltose, and trehalose. In a preferred embodiment,the carbohydrate is a disaccharide, specifically sucrose, having thestructure:

Whereby ester group is formed on the hydroxmethyl group present on theglucose portion of the sucrose compound—as discussed in greater detailherein.

According to the present invention, the humectant may be a blend of a(I) first ester-containing compound and a (II) second ester-containingcompound. The (I) first ester-containing compound may have the FormulaI:

Wherein R_(a) comprises at least one ketone group that is optionallyseparated from the ester groups by a C1-C24 straight or branchedaliphatic chain. R′_(a) may comprise a C1-C24 straight or branchedaliphatic chain that is free of ketone groups. In a preferred embodimentfor the (I) first ester-containing, R_(a) comprises a single ketonegroup and R′_(a) is a C1-C4 straight aliphatic chain. In an even morepreferred embodiment, the (I) first ester-containing compounds has theformula:

Whereby the compound may be formed from the ester-forming reaction ofethanol and pyruvic acid. Pyruvic acid is a keto acid. Othernon-limiting examples of keto acid suitable in the formation of the (I)first ester-containing compound include acetoacetic acid, levulinicacid, and the like. Ethanol is a mono-functional alcohol. Othernon-limiting examples of mono-functional alcohol include methanol,ethanol, n-propanol, isopropanol, sec-butanol, isobutanol, n-butanol,methyl amyl alcohol, methyl butanol, cyclohexanol and any mixturesthereof.

The (II) second ester-containing compound may have the Formula II:

Wherein R_(b) comprises a C1-C24 straight or branched aliphatic chain,and R′_(b) comprises a compound derived from a carbohydrate. Thecarbohydrate may be one of the monosaccharide or disaccharide compoundspreviously discussed. In a preferred embodiment for the (II) secondester-containing compound, R_(b) is a C16-C24 straight aliphatic chainand R′_(b) is derived from a disaccharide compound. In an even morepreferred embodiment, the (II) second ester-containing compound, R_(b)is a C16-C24 straight aliphatic chain and R′_(b) is a glucose containingdisaccharide, whereby the ester bond is directly bonded to the glucoseportion of the disaccharide. A non-limiting example of the (II) secondester-containing compounds has the formula:

Whereby the compound may be formed from the ester-forming reaction ofsucrose and arachidic acid. Arachidic acid is a saturated fatty acid.Other non-limiting examples of saturated fatty acids suitable in theformation of the (II) second ester-containing compound include caprylicacid, capric acid, lauric acid, myristic acid, palmitic acid, stearicacid, behenic acid, lignoceric acid, cerotic acid, and the like.

The (I) first ester-containing compound and the (II) secondester-containing compound may be present together in a single blend,whereby the (I) first ester-containing compound and the (II) secondester-containing compound are present in relative amounts. The amount ofthe (I) first ester-containing compound and the (II) secondester-containing compound in the single blend may be the same ordifferent.

As discussed, the humectant may be hydrophobic. As a result, thepresence of the humectant in the edge coating 230 may result in thebuilding panel 100 having enhanced hydrophobicity. According to thepresent invention, the term “hydrophobicity” or “hydrophobic” means acomposition that is extremely difficult to wet and is capable ofrepelling liquid water under atmospheric conditions. Thus, as usedherein, the term “hydrophobic” refers to a surface that generates acontact angle of greater than 90° with a reference liquid (i.e. water).

The notion of using the contact angle made by a droplet of liquid on asurface of a solid substrate as a quantitative measure of the wettingability of the particular solid has also long been well understood.Wetting is the ability of a liquid to maintain contact with a solidsurface, resulting from intermolecular interactions when the two arebrought together. The degree of wetting (wettability) is determined by aforce balance between adhesive and cohesive forces. If the contact angleis greater than 90° for the water droplet to the substrate surface thenit is usually considered to be hydrophobic.

The side surface 113 of the building panel 100 according to the presentinvention may exhibits a water contact angle of at least about 90°. Atthis contact angle, most common waters and oils (e.g., fingerprint oils)will not wet the side surface 113 of the building panel 100—therebymaking the building panel 100 resistant to smudging during installation.In some embodiments, the side surface 113 of the building panel 100according to the present invention may exhibits a water contact angle ofat least about 107°.

The edge coating 230 may comprise pigment. The pigment present in theedge coating 230 may be an inorganic pigment. The pigment may be aparticle exhibiting one of the previously discussed colors with respectto the color coating 200. Thus, the edge coating 230 may also bereferred to herein as a “color coating” 230. Non-limiting examples ofinorganic pigment include particles of carbon black, graphite, graphene,copper oxide, iron oxide, zinc oxide, calcium carbonate, manganeseoxide, titanium dioxide and combinations thereof. The inorganic pigmentsmay include individual particles having colors selected from, but notlimited to, red, blue, yellow, black, green, brown, violet, white, greyand combinations thereof. The particles that make up the first pigmentmay have a particle size ranging from about 15 nm to about 1000μm—including all sizes and sub-ranges there-between.

The pigment may be present in an amount ranging from about 1 wt. % toabout 80 wt. % based on the total dry-weight of the edge coating230—including all wt. % and sub-ranges there-between. Similar to thephrase “dry-state”—the phrase “dry-weight” refers to the weight of acomponent or composition without including any additional weight ofliquid carrier. Thus, when calculating the dry weight of a component orcomposition, the calculation should be based solely on the weight of thesolid components (e.g., dispersant, pigment, binder, etc.), and shouldexclude any amount of residual liquid carrier that may still be presentfrom the wet-state.

In a preferred embodiment, the pigment may be present in an amountranging from about 20 wt. % to about 70 wt. % based on the totaldry-weight of the edge coating 230 including all wt. % and sub-rangesthere-between. In a preferred embodiment, the pigment may be present inan amount ranging from about 40 wt. % to about 65 wt. % based on thetotal dry-weight of the edge coating 230—including all wt. % andsub-ranges there-between.

The edge coating 230 may further comprise binder. The binder may bepresent in the edge coating 230 in an amount ranging from about 1 wt. %to about 50 wt. % based on the total dry-weight of the edge coating230—including all amounts and sub-ranges there-between. The binder maybe polymeric. In a preferred embodiment, the binder may be present inthe edge coating 230 in an amount ranging from about 10 wt. % to about35 wt. % based on the total dry-weight of the edge coating 230—includingall amounts and sub-ranges there-between. The binder may be polymeric.The binder may have a glass transition temperature (“Tg”) that rangesfrom about 15° C. to about 30° C.—including all temperatures andsub-ranges there-between.

Non-limiting examples of the first binder include polymers selected frompolyvinyl alcohol (PVOH), latex, an acrylic polymer, polymaleicanhydride, or a combination of two or more thereof. Non-limitingexamples of latex binder may include a homopolymer or copolymer formedfrom the following monomers: vinyl acetate (i.e., polyvinyl acetate),vinyl propinoate, vinyl butyrate, ethylene, vinyl chloride, vinylidenechloride, vinyl fluoride, vinylidene fluoride, ethyl acrylate, methylacrylate, propyl acrylate, butyl acrylate, ethyl methacrylate, methylmethacrylate, butyl methacrylate, hydroxyethyl methacrylate,hydroxyethyl acrylate, styrene, butadiene, urethane, epoxy, melamine,and an ester. Preferably the binder is selected from the groupconsisting of aqueous lattices of polyvinyl acetate, polyvinyl acrylic,polyurethane, polyurethane acrylic, polystyrene acrylic, epoxy,polyethylene vinyl chloride, polyvinylidene chloride, and polyvinylchloride.

The binder may be thixotropic. The term “thixotropic” refers to acomposition that has a high viscosity (e.g., 40,000 cps) at low-shearand a low viscosity (e.g., 800 cps) at high-shear. Non-limiting examplesof thixotropic binder include polymers selected from polyvinyl alcohol(PVOH), aforementioned latex, acrylic polymer, polymaleic anhydride, ora combination of two or more thereof.

The binder may be a thixotropic polymeric having a Tg that is less thanroom temperature (“Tm”). In a preferred embodiment, the second binder isa thixotropic polymeric binder having a Tg less than 20° C.—preferablyless than 19° C. The binder may be film-forming and having a minimumfilm-forming temperature of about 12° C. The term “film-formingtemperature” refers to the temperature at which a composition forms afilm.

The edge coating 230 may further comprise a dispersant. The dispersantmay be present in the edge coating 230 in an amount ranging from about0.1 wt. % to about 2.0 wt. % based on the total dry-weight of the edgecoating 230 including all wt. % and sub-ranges there-between. In apreferred embodiment, the dispersant may be present in the edge coating230 in an amount ranging from about 0.1 wt. % to about 1.5 wt. % basedon the total dry-weight of the edge coating 230—including all wt. % andsub-ranges there-between. The dispersant may be ionic in nature—i.e.,comprise one or more ionic groups such as anionic group or cationicgroup. In a preferred embodiment, the ionic group is anionic.

According to some embodiments, the dispersant may comprise an anionicpolyacrylic polymer having a salt group formed from a neutralization ofan acid group with a compound forming a cation. For examples, thepolymer may comprise one or more pendant side chains comprising aterminal carboxylic acid group that is neutralized with sodium orammonia to form a carboxylate anion and a sodium cation and/or ammoniumcation. Alternatively, the polymer may comprise one or more pendant sidechains comprising a terminal sulfonic acid group that is neutralizedwith the aforementioned sodium or ammonia. compounds to form a saltgroup.

The edge coating 230 may further comprise a wetting agent. The wettingagent may be present in the edge coating 230 in an amount ranging fromabout 0.2 wt. % to about 2.0 wt. % based on the total dry-weight of theedge coating 230—including all wt. % and sub-ranges there-between. In apreferred embodiment, the wetting agent may be present in the edgecoating 230 in an amount ranging from about 0.8 wt. % to about 1.8 wt. %based on the total dry-weight of the edge coating 230—including all wt.% and sub-ranges there-between.

The wetting agent is a type of surfactant that lowers the surfacetension between two liquids or between a liquid and a solid. The wettingagent may comprise a hydrophobic portion and a hydrophilic portion. Thehydrophobic portion may be a long aliphatic chain derived from a fattyalcohol. In other embodiments, the hydrophobic portion may comprise oneor more aromatic groups. The wetting agent may be non-ionic, whereby thehydrophilic portion includes an ethoxylated chain. In a preferredembodiment, the wetting agent is non-ionic, whereby the hydrophobicportion comprises at least one aromatic group. The wetting agent maycomprise two or more aromatic groups. Non-limiting examples of wettingagent include three aromatic groups, such as tristyrylphenol ethoxylate.

The solids content of the edge coating composition may range from about70 wt. % to about 90 wt. %—including all wt. % and sub-rangesthere-between. In a preferred embodiment, the solids content of the edgecoating composition may range from about 72 wt. % to about 78 wt. %based on the total weight of the edge coating composition—including allwt. % and sub-ranges there-between. In a preferred embodiment, thesolids content of the edge coating composition may range from about 75wt. % to about 76 wt. % based on the total weight of the edge coatingcomposition—including all wt. % and sub-ranges there-between. In someembodiments, the edge coating composition may have a solids content ofat least 75 Wt. % based on the total weight of the edge coatingcomposition.

The edge coating composition may be thixotropic. The edge coatingcomposition may have a viscosity ranging from about 1,000 cps to about20,000 cps as measured by a Brookfield viscometer at 10 RPM using a #4spindle at room temperature—including all viscosities and sub-rangesthere-between. In a preferred embodiment, the edge coating compositionmay have a viscosity ranging from about 4,000 cps to about 8,000 cps asmeasured by a Brookfield viscometer at 10 RPM using a #4 spindle at roomtemperature—including all viscosities and sub-ranges there-between. Theedge liquid-based coating composition may comprise water as the liquidcarrier, wherein the liquid carrier comprises less than 1 wt. % of VOCsolvent.

The edge coating composition (i.e., wet-state) may be applied to thebody side surface 123 in an amount ranging from about 10 g/m² to about200 g/m²—including all sub-ranges and values there-between. The edgecoating composition may be applied to the side surface 123 of the body120 by spray, roll, wheel coater, and vacuum coating. The edge coatingcomposition may be applied by a DVD edge coating unit.

The edge coating composition may be dried at an elevated temperature fora drying period—wherein the elevated temperature ranges from about 120°C. to about 240° C.—including all sub-ranges and temperaturethere-between. The drying period may range from about 10 seconds toabout 120 seconds—including all sub-ranges and temperaturethere-between. The resulting edge coating 230 (i.e., in the dry-state)may be present in an amount ranging from about 7.5 g/m² to about 150g/m²—including all amounts and sub-ranges there-between.

According to other embodiments, the building panel 100 may comprise aface coating 210 applied to the upper surface 121 of the body 120. Theface coating 210 may comprise one or more of the previously discussedcolor pigments, humectants, and/or binders. The face coating 210 mayfurther comprise one or more of the previously discussed dispersantsand/or wetting agents. The face coating 210, in the dry-state, may bepresent on the upper surface 121 of the body 120 in an amount rangingfrom about 10 g/m² to about 132 g/m²—including all amounts andsub-ranges there-between.

The face coating 210 may comprise an upper surface 211 opposite a lowersurface 212. The face coating 210 has a face coating thickness t₂—asmeasured from the upper surface 211 to the lower surface 212 of the facecoating 210. The face coating thickness t₂ may range from about 200 μmto about 500 μm—including all thicknesses and sub-ranges there-between.The lower surface 212 of the face coating 210 may be in direct contactwith the upper surface 121 of the body 120. The upper surface 211 of theface coating 210 may form at least a portion of the first major surface111 of the building panel 100—as discussed further herein.

The pigment may be present in the face coating 210 in an amount rangingfrom about 70 wt. % to about 95 wt. %—including all wt. % and sub-rangesthere-between—based on the total dry-weight of the face coating 210.

The binder may be present in the face coating 210 in an amount rangingfrom about 5 wt. % to about 20 wt. % based on the total dry-weight ofthe face coating 210—including all wt. % and sub-ranges there-between.The binder in the face coating 210 may be polymeric and have a glasstransition temperature (“Tg”) that ranges from about 21° C. to about 40°C.—including all temperatures and sub-ranges there-between.

The humectant of the present invention may be present in the facecoating 210 in an amount ranging from about 0.25 wt. % to about 2.5 wt.% based on the total dry-weight of the face coating 210—including allwt. % and sub-ranges there-between.

The dispersant may be present in the face coating 210 in an amountranging from about 0.05 wt. % to about 2.0 wt. % based on the totaldry-weight of the face coating 210—including all wt. % and sub-rangesthere-between. The wetting agent may be present in the face coating 210in an amount ranging from about 0.2 wt. % to about 1.5 wt. % based onthe total dry-weight of the face coating 210—including all wt. % andsub-ranges there-between.

The face coating composition has a high-solid's content. The solidscontent of the face coating composition may range from about 45 wt. % toabout 75 wt. %—including all wt. % and sub-ranges there-between. In apreferred embodiment, the solids content of the face coating compositionmay range from about 45 wt. % to about 65 wt. % based on the totalweight of the face coating composition—including all wt. % andsub-ranges there-between. In some embodiments, the face coatingcomposition may have a solids content of at least 50 wt. % based on thetotal weight of the face coating composition. In some embodiments, theface coating composition may have a solids content of at least 60 wt. %based on the total weight of the face coating composition.

The face coating composition may have a viscosity ranging from about 250cps to about 2,500 cps as measured by a Brookfield viscometer at 10 RPMusing a #4 spindle at room temperature—including all viscosities andsub-ranges there-between. In a preferred embodiment, the face coatingcomposition may have a viscosity ranging from about 350 cps to about1,500 cps as measured by a Brookfield viscometer at 10 RPM using a #4spindle at room temperature—including all viscosities and sub-rangesthere-between.

The face coating composition (i.e., in the wet-state) may be applied tothe upper surface 121 of the body 120 in an amount ranging from about 26g/m² to about 220 g/m²—including all sub-ranges and valuesthere-between. The face coating composition may be applied to the uppersurface 121 by roll coating, brush coating, and spray coating, and/orcurtain blade.

Once applied to the upper surface 121 of the body 120, the face coatingcomposition may be dried in a conventional oven at an elevatedtemperature for a drying period. The elevated temperature may range fromabout 67° C. to about 232° C.—including all sub-ranges and temperaturethere-between. In some embodiments, the elevated temperature may rangefrom about 67° C. to about 190° C.—including all sub-ranges andtemperature there-between. The drying period may range from about 10seconds to about 120 seconds—including all sub-ranges and temperaturethere-between. The resulting face coating 210 may be present on theupper surface 121 of the body 120 in an amount ranging from about 10g/m² to about 132 g/m²—including all amounts and sub-rangesthere-between.

Although not shown, the building panel 100 of the present invention mayfurther comprise a non-woven scrim. The non-woven scrim may comprise anupper surface opposite a lower surface. The lower surface of thenon-woven scrim may be positioned immediately adjacent to and in directcontact with the upper surface 121 of the body 120. The face coating 210may be applied to the non-woven scrim such that the lower surface 212 ofthe face coating 210 is in direct contact with the upper surface of thenon-woven scrim.

Referring now to FIGS. 1 and 4, the resulting building panel 100 maycomprise the face coating 210—whereby the first major surface 111 of thebuilding panel 100 comprises the upper surface 211 of the face coating210 and the face coating 210 comprises pigment and humectant. Thus, inthe installed state, at least a portion of the upper surface 211 of theface coating 210 faces the active room environment 2. The face coating210 may be substantially continuous. The term “substantially continuous”means less than 5% of the available surface area on the referencedsurface contains pin-holing or blistering.

According to other embodiments, the building panel 100 may comprise asurface coating 200 applied to the side surface 123 of the body 120 toform an edge coating 230. The edge coating 230 may comprise one or moreof the previously discussed pigments and humectant.

According to the embodiments where the building panel 100 comprises theedge coating 230, the side surface 113 of the building panel 100 maycomprise the edge coating 230. Specifically, the side surface 113 of thebuilding panel 100 may comprise the outer surface 231 of the edgecoating 230. Thus, the outer surface 231 of the edge coating 230 may forthe upper portion 113 a and the lower portion 113 b of the side surface113 of the building panel 100. Specifically, the upper portion 113 a ofthe side surface 113 may comprise an upper edge coating portion 231 aand the lower portion 113 b of the side surface 113 may comprise a loweredge coating portion 231 b.

Although not pictured, some embodiments of the present invention includea building panel comprising a surface coating 200 comprising only theedge coating 230. Specifically, the building panel 100 may comprise afirst major surface opposite a second major surface and a side surfaceextending there-between. The side surface 113 of the building panel 100may comprise the edge coating 230, the first major surface 111 of thebuilding panel 100 may comprise the upper surface 121 of the body 120and the second major surface 112 of the building panel 100 may comprisethe lower surface 122 of the body 120.

Although not pictured, some embodiments of the present invention includea building panel comprising a surface coating 200, wherein the surfacecoating 200 comprises only the face coating 210. Specifically, thebuilding panel 100 may comprise a first major surface 111 opposite asecond major surface 112 and a side surface 113 extending there-between.The first major surface 111 of the building panel 100 may comprise theupper surface 211 of the face coating 210, the second major surface 112of the building panel 100 may comprise the lower surface 122 of the body120, and the side surface 113 of the building panel 100 may comprise thebody side surface 123.

Referring now to FIG. 4, building panels 300, 400, 500 are illustratedin accordance with other embodiments of the present invention. Thebuilding panels 300, 400, and 500 are similar to building panel 100except as described herein below. The description of building panel 100above generally applies to building panels 300, 400, and 500 describedbelow except with regard to the differences specifically noted below. Asimilar numbering scheme will be used for the building panels 300, 400,and 500 as with building panel 100 except that the 300-, 400-, and500-series of numbers will be used.

Referring now to FIG. 5, the building panel 500 may be installedaccording to the second variation, as described herein. The buildingpanel 500 may be positioned such that the upper portion 513 a of theside surface 513 is below the horizontal flange 31, thereby extendinginto the active room environment 2. In the second variation, the lowerportion 513 b of the side surface 513 is above the horizontal flange 31extending into the plenum space 3. In the second variation, the firstmajor surface 511 and the upper portion 513 a of the side surface 513 ofthe building panel 500 is exposed to the active room environment 2. Inthe second variation, the lower portion 513 b of the side surface 513may be concealed from the active room environment 2. The lower portion513 b of the side surface 513 may be adjacent to at least a portion ofthe vertical web 32 as viewed along a horizontal direction. The lowerportion 513 b of the side surface 513 as well as the second majorsurface 512 may be exposed to the plenum space 3.

According to these embodiments, the upper portion 513 a and the lowerportion 513 b may comprise the surface coating 200—specifically, thefirst face coating 210. According to these embodiments, the first majorsurface 511 may comprise the surface coating 200—specifically, the edgecoating 230. Therefore, the surface coating 200 may be exposed to theactive room environment on the first major surface 511 and the upperportion 513 a of the side surface 513 of the building panel 500 in theinstalled state.

The invention will be described in greater detail by way of specificexamples. The following examples are offered for illustrative purposesand are not intended to limit the invention in any manner.

EXAMPLES

The experiments provided herein use the following humectantcompositions:

-   -   Humectant A (“HA”): blend of ester-containing humectants        including sugar based esters and glycol-based esters at 65 wt. %        solids and 35 wt. % water.    -   Humectant B (“HB”): propylene glycol    -   Humectant C (“HC”): ether-containing humectant (dipropylene        glycol monoethylether)

The binder used in the following examples includes a carboxylatedpolyvinyl acetate homopolymer at a solid's content of 50 wt. % andhaving a pH ranging between 7 and 8. The experiments use a pigmentcomposition that is a blend of TiO₂, CaCO₃, and calcined diatomaceousearth. The thickener used includes a blend of hydroxyethyl cellulose andhydrous magnesium aluminum-silicate. The experiments provided herein mayalso use the following dispersing agents:

-   -   Dispersing Agent 1 (“DA1”): ionic surfactant (sodium        polyacrylate)—commercially available as Nopcote 63900    -   Dispersing Agent 2 (“DA2”): non-ionic surfactant—commercially        available as TMN-6

Each example was prepared by mixing together the components at 23° C.(room temperature). The formulations of each example are set forthherein in Table 1. The coating compositions were applied to fibrousbodies formed from inorganic fiber—e.g., mineral wool.

TABLE 1 Ex. Ex. Wt. % Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8Ex. 9 10 11 Water 13.0 14.2 14.4 12.5 12.5 10.5 13.4 11.5 9.5 11.5 9.5Binder 21.1 21.1 21.1 21.1 21.2 21.2 19.6 21.2 21.2 21.2 21.2 HA — — — —— — — — — 1.0 3.0 HB — — — — — 2.0 — — — — — HC — — — — — — 5.8 1.0 3.0— — Dispersing 0.5 0.1 0.2 — — — — — — — — Agent 1 Dispersing 0.3 0.10.2 0.2 0.2 0.2 0.1 0.2 0.2 0.2 0.2 Agent 2 Pigment 42.6 42.6 44.0 44.042.0 42.0 38.8 42.0 42.0 42.0 42.0 Wetting Agent — — — 1.0 1.0 1.0 0.91.0 1.0 1.0 1.0 Flame 17.0 17.0 18.5 18.5 17.6 17.7 16.3 17.7 17.7 17.717.7 Retardant Mica 4.0 — — 0.5 4.0 4.0 3.7 4.0 4.0 4.0 4.0 Kaolin — 4.01.0 1.0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Thickener 0.6 0.6 0.3 0.5 0.5 0.30.4 0.3 0.3 0.3 0.3 Biocide 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1Defoamer 0.8 0.2 0.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Solid's 75.6 75.475.1 75.5 75.8 76.6 75.6 75.0 75.0 76.0 76.5 Content Density (g/mL) —1.65 1.69 1.63 1.68 1.57 1.57 1.64 1.39 1.67 1.62

As demonstrated by Table 1, Examples 6-11 are exemplary of the coatingcomposition of the present invention as they contain humectants, andExamples 10 and 11 are particularly preferred as the humectant is anester-containing humectant. Each coating composition, however, containsabout the same solid's content, whereby the liquid carrier is water. Theviscosity of each mixture was then measured using a #4 spindle atvarious RPMs. Additionally, each coating composition was run through aDVD edge coating unit, whereby the viscosity of each coating compositionwas closely monitored. The results of the viscosity measurements are setforth below in Table 2.

TABLE 2 Ex. Ex. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 1011 Initial Viscosity Measurement (cps)  0.5 rpm — 196000 100800 11280046400 64800 79200 80000 185600 49200 57200  10 rpm 5120 22600 7240 90204120 5010 6320 7280 15920 5020 6480  60 rpm — 5187 1700 2493 1253 14831960 2167 4247 1617 2227 100 rpm — 3492 1178 1800 920 1136 1468 15282916 1164 1630 Humectant None None None None None B C C C A A Increasein Y Y Y Y N N N N N N N Viscosity After 1 Hour Increase in N/A Y Y Y YN N N N N N Viscosity After 2 Hour Proper N/A N N N Y N N N N Y YCoating Hardening After Cure Blistering N/A Y Y Y Y Y Y Y Y N N inCoating After Cure Cracking N/A Y Y Y Y N N Y Y N N in Coating AfterCure

Each coating composition was then placed into a DVD edge coating unit,whereby the coating composition was introduced into a reservoir fromwhich it recirculated through the DVD edge coating unit as a portion ofthe coating composition was applied to an edge of a fibrous body. Therecirculation of the coating composition continued for a period of onehour before the viscosity of the coating composition that remained inthe reservoir was measured again to determine whether there had been anincrease in viscosity. The results of each measurement for the firstone-hour period are set forth in Table 1. Regarding Example 1, while thecoating composition exhibited an initial viscosity of about 5,210 cpswhen tests on a Brookfield Viscometer with a #4 spindle at 10 RPM, after1 hour in the DVD edge unit, the viscosity had increased so much thatthe coating composition was too thick to apply to a fibrous body.Therefore, no further viscosity measurements could be made to thiscoating composition nor could this coating composition be applied to afibrous body through the DVD edge coating unit.

Regarding Examples 2-4, each coating composition exhibited an increasein viscosity after just one-hour in the DVD edge coating unit. Theincrease in viscosity is undesirable as it indicates poor pot-life andunsuitable for large-scale manufacturing. The coating compositions ofExamples 2-4 were then further recirculated in the DVD edge coating unitfor a second hour, during which the coating compositions continued to beapplied to an edge of fibrous bodies. At the end of the second hour theviscosities of each coating composition had increased to a point wherethey were unworkable, requiring that DVD edge coating unit stop runningand the reservoir and the coating head of the DVD edge coating unit becleaned to remove build-up of the highly viscosity coating compositions.The work-stoppage and cleaning is highly undesirable. The coatingcomposition of Examples 2-4 that managed to be applied to the fibrousbody was then cured and evaluated for proper hardening, blistering,and/or cracking. Each coating composition of Examples 2-4 exhibitedinsufficient hardness (i.e., the coated building panel was too soft),blistering, and/or cracking.

It can be seen that by using only surfactants to affect viscosity (bothionic and non-ionic) does little to prevent or even prolong an increasein viscosity in the costing composition. In fact, even when additionalamounts of the ionic dispersant DA1 are added to the coating compositionaround the 25-minute mark, the reduction in viscosity is only temporary,whereby it then continues to increase with time again. Thus, while usingnon-ionic and/or ionic surfactants may be helpful to achieving thedesired initial viscosity, such surfactants do little to stabilize theviscosity over prolonged periods of processing time. while the additionviscosity may be relative stable for a non-humectant coating compositionfor one hour

Regarding Example 5, the addition of a wetting agent to the coatingcomposition may cause the coating composition to withstand an increasein viscosity for the first one-hour period. However, the addition of thewetting agent alone still does not prevent an increase in viscosity forprolonged periods of time, much like the other comparative coatings.Rather, the addition of the wetting agent only prevents an increase inviscosity until the second one-hour period in the DVD edge unit—whichindicates that surfactants and wetting agents alone cannot stabilize theviscosity over prolonged periods of processing time.

Referring now Examples 6-11, the addition of a humectant wetting agentto the coating composition provides enhanced viscosity stabilization asnone of the coatings exhibited a fatal increase in viscosity over thecourse of two hours in the DVD edge coating unit. Thus, the addition ofhumectant to the coating composition overcomes the setbacks in viscositystabilization when using only surfactants to control viscosity. However,as demonstrated by Examples 6-9, other setbacks may arise when using ahumectant other than an ester-containing humectant. For example, whenadding a glycol humectant (i.e., HB of Example 6) or an ether containinghumectant (i.e., HC of Examples 7-9), the viscosity may be stable over aprolonged period of time, however, the resulting coating compositionfails to properly cure and results in soft coatings that are inadequateas coatings on a building panel. Additionally, some coatings exhibitedblistering and/or cracking when comprising humectants other than theester-containing humectants of the present invention.

Referring now to Examples 10 and 11, when using the ester-basedhumectants of the present invention not only do the coating compositionsexhibit superior viscosity stabilization over prolonged periods of time(see FIG. 8), but it has been surprisingly discovered that suchcompositions can be applied and cured to coatings that have noblistering or cracking.

Additionally, it has been surprisingly discovered that the curedcoatings are hard coatings that are ideal on a building panels.Moreover, there has been a discovery of the surprising benefit of usingthe ester-based humectant (as compared to other humectants) withbuilding panel bodies that are formed from inorganic fiber.Specifically, when applying the coating composition that contains theester-based humectant, result inorganic fiber containing body maintainssufficient hardness and the body does not soften. TO the contrary, thecoating compositions comprising the non-ester containing humectantsresulted in the inorganic fiber bodies themselves to soften. This resultnot only creates inferior coatings but undermines the entire buildingpanel. These characteristics are summarized below in Table 3.

TABLE 3 Coating Inorganic Fiber Example Humectant Body Stiffness Ex. 10A Hard Ex. 11 A Hard Ex. 6 B Soft Ex. 7 C Soft Ex. 8 C Soft Ex. 9 C Soft

The aesthetic properties of each coating were then evaluated bymeasuring the color and gloss of each coating. The results of theaesthetic evaluation are set forth below in Table 4.

TABLE 4 Ex. Ex. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 1011 Color Values L — 96.32 96.81 96.77 96.03 — — 95.87 95.3 95.96 95.8 a— −0.39 −0.54 −0.55 −0.47 — — −0.48 −0.5 −0.53 −0.52 b — 3.78 3.52 3.413.4 — — 3.36 3.58 3.3 3.38 LR — 90.78 91.98 90.07 — — 89.69 88.34 89.9189.52 Gloss Values 85° — 2.4 2.9 — 3 — — 2.3 1.8 2.4 2.4

As demonstrated by Table 4, it has also been discovered that usinghumectant in a coating composition that is coated to at least one majorsurface of fibrous substrate does not result in a detrimental impact tothe color and gloss performance when compared to non-humectantcontaining coatings. Specifically, the color values of thehumectant-containing coating composition of Examples 8-11 are comparableto that of the coatings that do not comprise the humectant. Furthermore,it has been surprisingly discovered that when using the ester-basedhumectant (i.e., Examples 10 and 11), superior gloss values can beobtained in the final coating as compared to the coatings containinghumectants without an ester group (i.e., Examples 8 and 9).

What is claimed is:
 1. A coated building panel comprising: a bodycomprising a first major surface and a side surface that intersects thefirst major surface; a coating applied to at least one of the firstmajor surface or the side surface, the coating comprising: inorganicpigment; and a humectant comprising a first ester-containing compound;wherein the surface coating comprises a liquid carrier in an amount lessthan about 1 wt. % based on the total weight of the coating.
 2. Thecoated building panel according to claim 1, wherein the humectant ispresent in an amount ranging from about 0.5 wt. % to about 3.0 wt. %based on the total weight of the coating.
 3. The coated building panelaccording to claim 1, wherein the first ester-containing compound isnon-ionic.
 4. The coated building panel according to claim 1, whereinthe humectant is hydrophobic.
 5. (canceled)
 6. The coated building panelaccording to claim 1, wherein the humectant is a blend of the firstester-containing compound and a second ester-containing compound that isdifferent from the first ester-containing compound.
 7. The coatedbuilding panel according to claim 6, wherein first ester-containingcompound is a carbohydrate based ester.
 8. The coated building panelaccording to claim 6, wherein the second ester containing compound is aketo-acid based ester, wherein the second ester is the reaction productof acetoacetic acid and a mono-functional alcohol having a C1-C12 carbonchain. 9.-10. (canceled)
 11. The coated building panel according toclaim 1, wherein the inorganic pigment has a particle size ranging fromabout 15 nm to about 800 μm.
 12. The coated building panel according toclaim 1, wherein the coating is present in an amount ranging from about7.5 g/m² to about 150 g/m².
 13. (canceled)
 14. The coated building panelaccording to claim 1, wherein the inorganic pigment is present in anamount ranging from about 30 wt. % to about 75 wt. % based on the totalweight of the coating.
 15. The coated building panel according to claim1, wherein the coating further comprises a polymeric binder
 16. Thecoating building panel according to claim 15, wherein the polymericbinder has a glass transition temperature ranging from about 15° C. toabout 30° C.
 17. The coated building panel according to claim 15,wherein the polymeric binder is present in an amount ranging from about1 wt. % to about 30 wt. % based on the total weight of the coating. 18.The coated building panel according to claim 1, wherein the bodycomprises inorganic fiber selected from mineral wool, fiberglass, rockwool, slag wool, and combinations thereof. 19.-54. (canceled)
 55. Abuilding material comprising inorganic fiber; inorganic pigment;polymeric binder; and a humectant comprising a first ester-containingcompound.
 56. The building material according to claim 55, wherein thefirst ester-containing compound is non-ionic.
 57. The building materialaccording to claim 55, wherein the humectant is hydrophobic.
 58. Thebuilding material according to claim 55, wherein the humectant is ablend of the first ester-containing compound and a secondester-containing compound that is different from the firstester-containing compound, wherein first ester-containing compound is acarbohydrate based ester and the second ester is the reaction product ofacetoacetic acid and a mono-functional alcohol having a C1-C12 carbonchain. 59.-62. (canceled)
 63. The building material according to claim55, wherein the inorganic fiber is selected from mineral wool,fiberglass, rock wool, slag wool, and combinations thereof.
 64. A coatedbuilding panel comprising: a fibrous body comprising a first majorsurface and a side surface that intersects the first major surface; acoating applied to at least one of the first major surface or the sidesurface, the coating comprising: inorganic pigment; and a humectantcomprising a blend of the first ester-containing compound and a secondester-containing compound that is different from the firstester-containing compound, wherein the first ester-containing compoundis a carbohydrate based ester and the second ester-containing compoundis a keto-acid based ester. wherein the surface coating comprises aliquid carrier in an amount less than about 1 wt. % based on the totalweight of the coating.